(1) Field of the Invention
The present invention relates to a laser functional device provided with a laser luminescent element and presenting various functions between an input light and an output light, and particularly formed such as a optoelectronically fundamental function device which is easily miniaturized and integrated.
(2) Description of the Prior Art
Various kinds of conventional devices utilizing an electro-optical effect have been developed for high speed optical data processing and for optical communication.
However, most of these conventional laser functional devices are formed such as a light passing therethrough is controlled by an electro-optical effect element applied with a voltage representing information, so that these conventional devices cannot be regarded as a genuine optical active device such as a desired amount of self-generated output light can be obtained in response to an input light, that is, a so-called light input to light output device.
On the other hand, one of devices of this kind which have been vigorously developed in the last few years is an active bistable optical device, namely, so-called BOD. This device BOD is a genuine light input to light output device of the feedback type in which an optical function element is excited by feeding back a voltage produced in proportion to an intensity of an output light thereof, and further a hysteresis characteristic is presented between output and input lights of this device BOD. Accordingly, this device BOD has an inherent potential for optical switching, optical memory, binary logic, differential amplification, optical transistor, discrimination, clipping, limiting, pulse shaping and the like and further for performing a number of optical digital data processing functions. For instance, a Fabry-Perot resonator having an intrinsic nonlinear medium and an optical modulator having a hybrid configuration imposed with an electrical feedback control have been developed for this device BOD.
However, this conventional optical bistable device is also no more than a passive optical device containing no light source therein. Because the light source is indispensable for proper operation, it is inevitably required that the BOD device to be combined with a separately provided light source. Consequently, these conventional BOD devices cannot function as key elements for the optical system in the integrated structures.